I believe nationalism also can absolutely be healthy. Because there's big difference between nationalism of empires and nationalism of colonies.
Palestinian Fatah would be good example of left wing nationalism, or "liberatory nationalism". Because when somebody out there actually tries to wipe out your culture and identity, and possibly just physically erase your people - nationalism starts to absolutely make sense. And it then becomes anti-imperialistic and anti-fascist.
Taco Don already functionally stopped all aid and arms supply to Ukraine and trying his hardest to ignore Ukraine, and will probably chicken out from helping Taiwan defend itself too in case latter gets invaded.
So that's just China being asshole too and wanting Russia to succeed, because that'd mean you can take a dump on international laws and have benefits that outweigh repercussions.
If whatever remains of free democratic world won't get its shit together soon - we will just get picked apart eventually by those last iteration imperialists.